A telephone switching apparatus such as a key telephone apparatus and a private branch exchange (PBX (Private Branch Exchange)) is equipped with an automatic call recording function.
This call recording function is provided to record, for example, an unsolicited telephone call such as a nuisance telephone call, a threatening telephone call and a fraud telephone call, and a call log. A main apparatus of a key telephone apparatus accommodating an extension telephone is equipped with a unit for accumulating voices. Therefore, every time a call is made, the main apparatus of the key telephone apparatus can record the call.
Examples of the automatic call recording function of the telephone switching apparatus include a technique disclosed in Patent Literature 1.